US 3623891 A
Description (OCR text may contain errors)
Nov. 30, 1971 F. 0. COFFEY 3,623,891
PACKAGE AND METHOD FOR FORMING SAME Filed March 28, 1969 1x55455444!eeaeqaqaeqzqyaezeaq z4!a?254424441!!!(la ed dIII"IIIIII'I'I'II'I'I'II FIG.6 l3 INVENTOR FRANK o. COFFEY I, o I I!IIIIIIIIIIIIIIIIlIIIIIIIlIII/IIIIIIIIIA lllllllzlllilllllllI'll". I: M? f M 7 I I United States Patent 3,623,891 PACKAGE AND METHOD FOR FORMING SAME Frank O. Coffey, Glenview, Ill., assignor to Kraftco Corporation, New York, N.Y. Filed Mar. 28, 1969, Ser. No. 811,347
Int. Cl. 1365b 25/06 US. Cl. 99-178 11 Claims ABSTRACT OF THE DISCLOSURE The present invention relates generally to the packaging of cheese products in metallic foil and, more particularly, to the packaging in metallic foil of a cheese product which causes the metal foil to corrode when in contact therewith.
Metal foils, such as aluminum foil or tinfoil, are desirable for use in packagingparticularly in the packaging of perishables such as cheese. They lend themselves well to printing techniques, they are highly impervious to moisture and gas vapor, and they are relatively easy to work with during the packaging operation. Metal foil, however, is subject to corrosion when used in direct contact with moist or acidic food materials, such as natural or processed cheese. Consequently, metal foils are usually provided with a corrosion resistant coating on the surface adjacent the food material. That is, the metal foil is usually used in combination with another film material in a laminate form, or protective surface coating such as wax and/or plastic resin.
Neverthless, when laminated metal foil packaging materials are used to package moist or acidic foods, such as cheese, corrosion problems are still encountered at the edges of the wrapping sheet where the coating may not be present.
It is an object of the present invention to provide an improved package for cheese utilizing metal foil. It is another object of the invention to provide a metal foil package for food material which is not subject to corrosion of the metal foil. It is a further object of the present invention to provide an improved method for packaging cheese with metal foil. It is a still further object of the present invention to provide a method for packaging cheese in a metal foil packaging material wherein corrosion of the metal foil does not occur.
These and other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings, wherein:
FIG. 1 is a perspective View of a package embodying various of the features of the invention;
FIG. 2 is a cross sectional view taken along line 22 of FIG. 1;
FIG. 3 is a cross sectional view taken along line 33 of FIG. 1;
FIG. 4 is a schematic view illustrating a preferred method of forming the package of FIG. 1;
FIG. 5 is an enlarged fragmented sectional view of the package embodying various of the features of the invention; and
FIG. 6 is an enlarged fragmented sectional view corresponding to FIG. 5 but without the features of the inven tion.
Generally, in accordance with various of the features of the invention, a package for cheese units is provided from metal foil wrapping material which has been coated on at least one of its larger surfaces with a material which is corrosion resistant. The package is formed so that the lowermost edge of the wrapper in contact with the unit being packaged is turned under to provide a cuif.
Referring now more particularly to the drawing, there is illustrated a package '11 which can contain various products but the illustrated embodiment, by way of example, comprises a single slice of cheese enclosed in a segment or piece 15 of sheet wrapping material. The sheet 15 includes a layer 17 of a metallic foil (such as aluminum foil) provided on one of its two larger surfaces with a continuous acid impervious coating 19 which is not subject to corrosion when placed in contact with the acid of the cheese. Ideally, this coating is also a thermoplastic material so that the sheet can be heat sealed to itself at appropriate locations. The coating may be selected from any known materials for coating sheet wrapping material. These materials include polyolefins, such as polyethylene or vinyl plastics, polyesters, epoxy materials in combination with a heat sealable layer and polyamides. In a preferred embodiment, the coating is polyethylene or a vinyl plastic.
The sheet 15 has opposed edges 21 and 23, and edges 25 and 27 transverse to the opposed edges. It is contemplated that the sheet 15 be cut from a continuous web 29 (FIG. 4) fed from a roll or coil, in which case the opposed edges 21 and 23 define segments of the longitudinal side edges of the web and the transverse edges 25 and 27 are formed when the web is cut transversely. In such a case, the sheet is rectangular, with the opposed edges 21 and 23 parallel to each other and perpendicular to the transverse edges 25 and 27, which are also mutually parallel.
The sheet 15 is formed about the cheese slice 13 with the coating 19 adjacent the surfaces of the slice. It defines a bottom panel 31 and top flaps 33 and 3-5 which overlie the upper surface of the slice as shown. As will be noted in FIG. 2, the flaps 33 and 35 define a greater area than the bottom panel 3 1. That is, the sum of the widths of the flaps 33 and 35, as measured from the folds at the edges of the slice to the opposed edges 21 and 23 of "the sheet, is greater than the width of the slice. Thus, the flap 33 underlies and is overlapped by the flap 35.
It has been found that the edges 21, 23, 25 and 27 of the sheet 15 are generally not coated sufficiently to prevent corrosion of the metal at the edge. Insofar as the edges 25.and 27 are concerned this is due at least in part to the fact that these edges have been freshly cut from a web after the coating was applied. The edges 21 and 23 in most instances will also be cut after the web is coated as a result of an edge trimming operation. Thus, the metallic foil layer, although inaccessible over one entire surface of the sheet 15, is exposed on the opposite surface as well as along the four edges of the sheet. It will be appreciated that the form of wrap thus far described, without further modification, would locate the opposed edge 21, along which the metal foil layer 17 is exposed, immediately adjacent the cheese, but separated from the cheese by the width of the coating, as shown in FIG. 6. It has been observed that when cheese is wrapped in this manner ,a situation is created under which the foil is likely to corrode. Surprisingly, it has been found that if the sheet is arranged so that the Wrapper edge 21 is folded back upon itself so that the edge 21 is turned under the sheet 15 to provide a turned-under cuff 37, the metal foil will not be corroded during storage of the food material. Such folding under to provide a cuff places the metal foil in direct contact with the food material, as shown in FIG. 5.
The portion 39 of the sheet parallel to and immediately adjacent the opposed edge 23 is also folded back upon itself for reasons which will be explained shortly. After forming the package around the cheese slice with the turned under cuff 37 and turned back portion or lip 39, as shown in FIG. 2, the portions of the sheet adjacent the transverse edges 25 and 27 are pressed together under the application of heat to form seals 41.
It will be noted that there is no seal between the flaps 33 and 35 over the central portion of the package. That is, there is no seal extending transversely of the package in parallel relation to the opposed edges 21 and 23. Thus, the package may be easily opened by inserting the fingers or an instrument under the folded over portion 39 and then lifting the flap 35, thereby breaking the seal 41 between the fiap and the bottom panel 31. The flap 33 is similarly lifted to break the seals between that flap and the bottom panel. The slice 13 is thus exposed and readily accessible. In the opening of the package, the folded over edge portions 37 and 39 of the flaps 33 and 35 respectively serve to facilitate the grasping of the flaps for lifting.
It is not fully understood how the turned under cuff of the present invention acts to prevent corrosion. The exposed uncoated edge 21 of the metal foil is still in proximity to the cheese. Indeed, as can be seen in FIG. 5, if the metal foil is not coated on the exterior surface an entire section of the metal foil 43 is in direct contact wtih the cheese slice 13. This would lead one to believe that corrosion would occur more rapidly due to the greater sufrace area of metal foil exposed to the cheese. Yet, in accordance with the invention, it has been found that corrosion does not occur when a turned under cuff 37 of the metal foil is provided, as described, whether the metal foil is coated on both surfaces or not. Similarly, when the metal foil is not provided with a turned under cuff 37, as shown in FIG. 6, corrosion does occur whether the metal foil is coated with a protective coating on one or both surfaces.
While not wishing to be bound by any theory, it is believed that the corrosion of the metal foil, when located as shown in FIG. 6, is due to the establishment of a concentration gradient. This type of corrosion is referred to as concentration cell corrosion. It is known that two solutions of different concentrations will set up an electrical potential between them similar to that roduced by a battery. If oxygen is present in a liquid and the liquid is in contact with air, then the oxygen content of the liquid will remain substantially constant due to being replenished from the air. However, any liquid which is contained in small holes or cracks in a metal surface adjacent the liquid but separated slightly therefrom will not be able to obtain oxygen from the main body of liquid. When the oxygen of the liquid in the holes and cracks is exhausted, it is difficult for additional oxygen to get in to replace it. Therefore, the oxygen concentration of the liquid in the holes and cracks is different from that of the main body of liquid and a concentration cell is established. The minute electrical effect that is established is sufficient to make corrosion proceed quite rapidly.
In the package of the present invention, as shown in FIG. 5, the turned under cuff 37 establishes a pocket 38 which is substantially cut off from contact with air. The atmosphere of the pocket in contact with the edge portion 21 has a saturated solution of the liquid contained in the cheese slice 13. This present-s a constant oxygen environment to the edge portion 21 and prevents any concentration cells from forming. This in turn prevents any electrical effect from initiating corrosion. The same is true of a surface 43 of metal foil in contact with the cheese.
FIG. 4 illustrates a prefererd method of forming the package 11 of FIGS. 1-3. In accordance with the preferred method, the wrapping material is continuously fed in the form of the web 29 from a coil or roll 45 over a flat generally horizontal surface with the coating 19 uppermost. The cheese slices 13 are deposited one by one in spaced-apart relation on the moving web, and the longitudinal side edge portions of the web are brought upwardly on each side of the slices. As these side edge ortions are brought upwardly, the areas immediately adjacent the edges (which ultimately form the edges 21 and 23 of the sheet 15) are folded over, one inwardly and one outwardly, to provide the cuff 37 and lip 39 previously referred to. These longitudinal side edge portions are then placed in overlying relation to the cheese slices 13, with the portion to the right as viewed in FIG. 4 overlying the portion to the left. The envelope thus formed is then sealed and severed transversely to form packages 11, each containing an individually wrapped slice of cheese.
It should be apparent, of course, that the method could also be performed by bringing the web over slices moving on a conveyor, with the cuff and lip then being formed under the slices rather than over the slices. The method described, however, was chosen for ease of illustration.
EXAMPLE A group of packages was prepared in accordance with the present invention wherein single slices of process cheese were packaged. The overlapped flaps 33 of the packages were folded under a distance of one-quarter inch. The top flap 35 was placed in position over the top surfaces of the slices and folded upwardly one-quarter inch to form a lip 39. The portions of the wrapper adjacent the edges 25 and 27 were then heat sealed and the packages containing the single slices of processed cheese were stored. A second group of packages was similarly prepared except that the flaps 33 were not folded under. These packages were also placed in storage and the two groups of packages were observed from time to time.
At the end of two months storage time, the packages without the flaps 33 being folded under were observed to have become corroded at the junction of the edge 21 with the packaged processed cheese. The packages with the fold showed no such corrosion.
An improved package utilizing metal foil has thus been shown and described, together with a method of forming the package. The improved package having a turned under cuff provides a unique method for preventing corrosion of metal foil packages.
While various of the features of the invention have been shown and described with respect to one specific embodiment thereof, it should be apparent that various modifications may be made therein without departing from the scope of the invention.
Various of the features of the invention are set forth in the following claims.
What is claimed is:
1. A package comprising cheese enclosed on all sides by a piece of coated metallic wrapping material; said piece of wrapping material having two opposed edges and edges transverse to the opposed edges, said piece being formed so as to provide the lowermost of the opposed edges in contact with the article with a turned under cuff, said piece of wrapping material being wrapped around the cheese with the coating adjacent to and in contact with the cheese, with the opposed edges extending across the cheese, and with the portion of the piece adjacent one opposed edge in overlapping but unsealed relation to the portion of the piece adjacent the other opposed edge; the area of the lowermost overlapped portion of the piece adjacent the other opposed edge being folded back upon itself toward the cheese so as to provide said turned under cuff with the edge in contact with the cheese; the areas of the piece adjacent the edges transverse to the opposed edges being joined to enclose the cheese at such areas.
2. A package in accordance with claim 1, wherein the opposed edges of the piece of wrapping material are generally parallel.
3. A package in accordance with claim 1, wherein the metallic foil is coated with a thermoplastic material.
4. A package in accordance with claim 1, wherein the coating material is polyethylene.
5. A package in accordance with claim 1, wherein the coating material is a vinyl plastic.
6. A package in accordance with claim 1, wherein the piece of wrapping material is rectangular.
7. A package in accordance with claim 1, wherein the areas of the piece of wrapping material adjacent the edges transverse to the opposed edges are sealed together.
8. A package in accordance with claim 3, wherein the areas of the piece of wrapping material adjacent the edges transverse to the opposed edges are heat sealed together.
9. A package in accordance with claim 1, wherein the coating of the wrapping material is in direct contact with the surface of the cheese.
10. A method of wrapping cheese slices in metallic foil wrapping material having a continuous coating on one of its larger surfaces, said method comprising aligning the slices in a row and in spaced relation to each other in the row, disposing an elongated sheet of the wrapping material adjacent the row of slices with the longitudinal edges of the sheet generally parallel to the longitudinal axis of the row with the coating adjacent the slices, forming in an unsealed manner the elongated sheet of the wrapping material into an envolope enclosing the row of slices by bringing portions of the sheet adjacent the longitudinal edges into overlying relation with the slices with one of the portions overlapping the other, folding the area of the lowermost overlapped portion of the sheet adjacent the edge of that portion back upon itself toward the slices, and pinching the envelope together transversely between adjacent spaced slices to isolate the slices from each other.
11. A method in accordance with claim 10, wherein the envelope is sealed and severed transversely in the areas where it is pinched together between slices.
References Cited UNITED STATES PATENTS 2,600,216 6/1952 Denison 99-171 X 3,022,613 2/1962 Powers 53-28 3,291,377 12/1966 Eggen 206-58 X 3,405,861 10/1968 Bush 206-56 A2 X 3,536,501 10/1970 Work 99-171 TIM R. MILES, Primary Examiner US. Cl. X.R.
53-28; 99-171 LP; 206-46 F